#include <math.h>
#include <d3d9.h>
#include <d3dx9.h>
#include "HTCalc.h"
#include <stdlib.h>
#include <stdio.h>

float HTCalc::ObjectDensityFunc(D3DXVECTOR3 center, float radius, float softness, D3DXVECTOR3 point)
{
	float rsub12 = pow((radius - softness/2),2);
	float rsub02 = pow((radius + softness/2),2);
	float rsubx2 = pow((point.x - center.x),2) + pow((point.y - center.y),2) + pow((point.z - center.z),2);
	
	if(rsubx2 <= rsub12)
	{
		return 1.0f;
	}
	else if(rsubx2 >= rsub02)
	{
		return 0.0f;
	}
	else
	{
		return (rsub02 - rsubx2)/(rsub02 - rsub12);
	}
}

float HTCalc::Bias(float b, float t)
{
	return pow(t, log(b)/log(.5f));
}

float HTCalc::Gain(float g, float t)
{
	if(t < 0.5f)
	{
		return Bias(1 - g, 2 * t)/2;
	}
	else
	{
		return 1 - (Bias(1-g, 2 - (2 * t))/2);
	}
}

float HTCalc::Turbulence(D3DXVECTOR3 &point, double minFreq, double maxFreq)
{
	double t = 0;
	double f;
	for( f = minFreq; f <= maxFreq; f *= 2)
	{
		t+=abs(Noise(D3DXVECTOR3(f*point.x, f*point.y, f*point.z),f)/f);
		
	}
	return t;
}

double HTCalc::Noise(D3DXVECTOR3 point, double freq)
{
	double x1, y1, z1;
	x1 = .707*point.x-.707*point.z;
	z1 = .707*point.x+.707*point.z;
	y1 = .707*x1+.707*point.y;
	x1 = .707*x1-.707*point.y;
	float temp = ImprovedNoise(x1, y1, z1);
	return temp;
}

double HTCalc::ImprovedNoise(double x, double y, double z)
{

	int X = ((int)floor(x)) & 255,                  // FIND UNIT CUBE THAT
          Y = ((int)floor(y)) & 255,                  // CONTAINS POINT.
          Z =((int)floor(z)) & 255;
      x -= floor(x);                                // FIND RELATIVE X,Y,Z
      y -= floor(y);                                // OF POINT IN CUBE.
      z -= floor(z);
      double u = fade(x),                                // COMPUTE FADE CURVES
             v = fade(y),                                // FOR EACH OF X,Y,Z.
             w = fade(z);
      int A = p[X  ]+Y, AA = p[A]+Z, AB = p[A+1]+Z,      // HASH COORDINATES OF
          B = p[X+1]+Y, BA = p[B]+Z, BB = p[B+1]+Z;      // THE 8 CUBE CORNERS,

	  return lerp(w, lerp(v, lerp(u, grad(p[AA  ], x  , y  , z   ),  // AND ADD
                                     grad(p[BA  ], x-1, y  , z   )), // BLENDED
                             lerp(u, grad(p[AB  ], x  , y-1, z   ),  // RESULTS
                                     grad(p[BB  ], x-1, y-1, z   ))),// FROM  8
                     lerp(v, lerp(u, grad(p[AA+1], x  , y  , z-1 ),  // CORNERS
                                     grad(p[BA+1], x-1, y  , z-1 )), // OF CUBE
                             lerp(u, grad(p[AB+1], x  , y-1, z-1 ),
                                     grad(p[BB+1], x-1, y-1, z-1 ))));
}

void HTCalc::Initialize()
{
	int test[512] = { 151,160,137,91,90,15,131,13,201,95,96,53,194,233,7,225,140,36,103,30,69,142,8,99,37,240,21,10,23,
   190, 6,148,247,120,234,75,0,26,197,62,94,252,219,203,117,35,11,32,57,177,33,
   88,237,149,56,87,174,20,125,136,171,168, 68,175,74,165,71,134,139,48,27,166,
   77,146,158,231,83,111,229,122,60,211,133,230,220,105,92,41,55,46,245,40,244,
   102,143,54, 65,25,63,161, 1,216,80,73,209,76,132,187,208, 89,18,169,200,196,
   135,130,116,188,159,86,164,100,109,198,173,186, 3,64,52,217,226,250,124,123,
   5,202,38,147,118,126,255,82,85,212,207,206,59,227,47,16,58,17,182,189,28,42,
   223,183,170,213,119,248,152, 2,44,154,163, 70,221,153,101,155,167, 43,172,9,
   129,22,39,253, 19,98,108,110,79,113,224,232,178,185, 112,104,218,246,97,228,
   251,34,242,193,238,210,144,12,191,179,162,241, 81,51,145,235,249,14,239,107,
   49,192,214, 31,181,199,106,157,184, 84,204,176,115,121,50,45,127, 4,150,254,
   138,236,205,93,222,114,67,29,24,72,243,141,128,195,78,66,215,61,156,180
   };
	permutation = test;
	for(int i = 0; i < 256; i++)
	{
		HTCalc::p[256+i] = HTCalc::p[i] = HTCalc::permutation[i];
	}
}

double HTCalc::fade(double t) { return t * t * t * (t * (t * 6 - 15) + 10); }
double HTCalc::lerp(double t, double a, double b) { return a + t * (b - a); }
double HTCalc::grad(int hash, double x, double y, double z) {
      int h = hash & 15;                      // CONVERT LO 4 BITS OF HASH CODE
      double u = h<8 ? x : y,                 // INTO 12 GRADIENT DIRECTIONS.
             v = h<4 ? y : h==12||h==14 ? x : z;
      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
 }

int* HTCalc::p = new int[512];
int* HTCalc::permutation = NULL;

void HTCalc::Unload()
{
	delete p;
}